Protector for radio sets



' Nov. 19, 1929.

L. LUDWIG PROTECTOR FOR RADIO SETS Filed June 19. 1928 INVENTOR 1001 sZudvwy TTORNEY Patented Nov. 19, 1929 LOUIS LUDWIG, or BROOKLYN, NEWYORK PROTECTOR FOR RADIO SETS Application filed June 19,

My invention relates to protector for radio sets using commercialcurrent and has for its main object to provide a device which mayreadily be attached to any such set and which will effectively protectit from injuries, such as would be caused by an increase of thepotential of the current normally used, and to so construct the devicethat it will function as a fuse. A further object is to provide a deviceof few parts, small in size, neat in appearance and inexpensive tomanufacture.

These and other objects and advantages will be readily understood fromthe following description and from the accompanying drawing of apreferred embodiment, but it will be noted that modifications might bemade without departing from the scope of the. invention. In the drawing,

0 Fig. 1 is a crosssectional top View of the device,

Fig. 2 is a top view,

Fig. 3 is a cross-sectional end view taken on line 33, Fig. 1, and

Fig. 4 is a fragmental side view of one of the parts in the device.

The protector consists of a tubular body member 10, having a fixturesocket 11 inserted in one end and a two-pronged plug 12 inserted in theother end. A switch 13 is inserted in the side of the body member and aresistance coil 14 is secured in a cradle 15 attached on the inside ofthe body member.

The coil is constructed of a thin resistance 1;; wire 16 wound upon anasbestos cord 17 The asbestos cord is wound in a helix and imbedded in asuitable plastic material 18. The coil is so constructed as to allowonly a given voltage to pass through it to the set, any higher voltagewill be absorbed or cause the coil to burn out.

The various parts are electrically connected as follows. A wire 19connects the prong 20 of the plug 12 with one side of the switch 13, awire 21 connects the other side of the switch with the outer contact 22of the socket 11, one end of the resistance wire 16 is connected to thecenter contact 23 of the socket, and the other end of this wire isconnected to the prong 24. In operation the plug 12 is in- 1928. SerialNo. 286,702.

Patent is- In a device of the class described, an insulating tube, arecessed disc inserted in one end of said tube, two metal prongs securedon said disc in spaced relation, a lamp socket secured in the other endof the tube, a switch mounted in the side of the tube, a resistanceelement secured inside the tube, one of said prongs electricallyconnected through the switch with one contact of the lamp socket, andthe other prong connected through the resistance element with the otherlamp socket contact.

